Drupal Custom Theme Development

1. What is the difference between Drupal 7’s and Drupal 9’s architecture?

   While Drupal 7 runs on the PHPTemplate as its default theme engine, Drupal 9 uses Twig (which replaces the PHPTemplate as the default theme engine).

2. What is the difference between a Drupal base theme and a starterkit?

   The Drupal Starterkit theme is a command line tool that allows developers to start a new theme from scratch or from a template. On the other hand, in Drupal base themes, the sub-theme extends the base theme, and the base theme is used in runtime as part of your theme.

3. What is the best theme for building micro websites on Drupal?

   This is a needs-based decision. You can use the Micro theme module on Drupal to create microsites on Drupal for the specific needs of your industry, as micro websites for a product or specific project may need to incorporate the brand elements of the parent website.

4. Is it possible to use a Drupal 7 theme in Drupal 9 or Drupal 10 website?

   No, it is not possible to use a Drupal 7 theme in Drupal 9 or Drupal 10 websites. Drupal 7 uses PHPtemplate as the theme engine, whereas the latest versions of Drupal use twig theme engine. As Drupal themes uses HTML and CSS, it is possible to extract the HTML/CSS components from the Drupal 7 theme and reuse them in the Drupal 9 themes or Drupal 10 themes.

5. I am using Drupal 8; can I use the same theme in Drupal 9?

   Technically it is possible to use a theme created for Drupal 8 in Drupal 9 with minor changes. If there are lots of customizations, specifically theme preprocess functions, a Drupal 9 compatibility check needs to be done to enable the code to support Drupal 9 before using it there.

6. Is it possible to maintain a Drupal 9 theme compatible with Drupal 10?

   Yes, it is possible to maintain a Drupal 9 theme compatible with Drupal 10 by replacing all the functions that are deprecated in Drupal 10. If the developer closely follow the Drupal 10 releases, it will be easy to maintain a theme that is supported by Drupal 9 as well as Drupal 10 and when Drupal 10 get released, the theme can be used in a Drupal 10 website without any change.

7. Will Drupal support component-based theming? (Atomic design, patternlab, Storybook, etc.)

   Yes, Drupal will support component-based theming that will enable atomic design with the help of the Patternlab development environment through Twig. 

8. Should I go for a custom theme or off-the-shelf theme?

   An off-the-shelf theme is used when you need to get a website up and running quickly or want to show a proof of concept or prototype, or if the budget is really low. If you are looking to build a digital experience platform that should stand for the long term and support all the customer journeys you define and be unique to your brand, the best option is to go with the custom theme development.